KR20220068750A - Copolymer, method of producing the same and rubber composition comprising the same - Google Patents

Abstract

The present invention relates to a copolymer, a preparation method thereof, and a rubber composition comprising the same. More specifically, the copolymer of the present invention comprises: a repeating unit derived from a conjugated diene monomer; and a repeating unit derived from an aromatic vinyl-based monomer, wherein at least one of both ends of the copolymer is a functional group represented by chemical formula 1. A novel modified copolymer provided by the present invention can acquire an improved affinity for a filler such as silica.

Description

Copolymer, method of producing the same, and rubber composition comprising the same

The present invention relates to a copolymer, a method for producing the same, and a rubber composition comprising the same, and more particularly, to a modified conjugated diene modified with a novel structure capable of improving affinity with inorganic fillers and inhibiting aggregation between fillers It relates to a system and aromatic vinyl-based copolymer, a method for preparing the same, and a rubber composition comprising the same.

In response to the recent demand for low fuel consumption for automobiles, as a rubber material for tires, a conjugated diene-based polymer having low rolling resistance, excellent abrasion resistance, tensile properties, etc., and adjustment stability typified by wet skid resistance is required.

Carbon black and silica are used as reinforcing fillers for tire treads. When silica is used as reinforcing fillers, low hysteresis and wet skid resistance are improved. However, compared to carbon black on the hydrophobic surface, silica on the hydrophilic surface has a disadvantage of poor dispersibility due to low affinity with rubber. It is necessary to use a ring agent. Accordingly, a method has been made to introduce a functional group having affinity or reactivity with silica at the end of the rubber molecule, but the effect is not sufficient. In addition, in the case of the modified styrene-butadiene copolymerization, the production efficiency is low, and the effect of the modification may be insufficient.

For example, Korean Patent Application Laid-Open No. 10-2016-0071337 discloses a styrene-butadiene copolymer terminally modified with a specific aminosilane-based modifier, and this compound has the effect of improving fuel efficiency and traction through terminal modification. However, there is a limitation in that the method for preparing the denaturant is very difficult.

Accordingly, there is a need for a copolymer capable of obtaining excellent dispersibility by preventing agglomeration between fillers as well as affinity for inorganic fillers.

One aspect of the present invention is to provide a copolymer modified with a structure capable of improving affinity with inorganic fillers and further preventing aggregation between inorganic fillers.

Another aspect of the present invention is to provide a method for preparing the modified copolymer of the present invention.

Another aspect of the present invention is to provide a rubber composition comprising the modified copolymer of the present invention.

Another aspect of the present invention is to provide a tire manufactured from the rubber composition of the present invention with improved physical properties.

According to one aspect of the present invention, a repeating unit derived from a conjugated diene-based monomer; And a copolymer including a repeating unit derived from an aromatic vinylic monomer, wherein at least one terminal among a plurality of terminals of the copolymer includes a functional group represented by the following formula (1):

[화학식 1]

[Formula 1]

(In Formula 1,

R ¹ , R ² and R ⁵ are each independently selected from the group consisting of hydrogen, a hydroxy group, a hydroxy (C ₁ -C ₂₀ )alkyl group, and a straight-chain and branched (C ₁ -C ₂₀ )alkyl group;

R ³ and R ⁴ are each independently selected from the group consisting of N, S, O and Si;

R ⁶ , R ⁷ and R ⁹ are each independently selected from the group consisting of hydrogen, straight-chain and branched (C ₁ -C ₂₀ )alkyl groups;

R ⁸ may be selected from the group consisting of straight-chain and branched (C ₁ -C ₂₀ )alkylene groups, or may form a single bond or a divalent linking group between N and Si;

R ¹⁰ and R ¹¹ are each independently selected from the group consisting of straight-chain and branched (C ₁ -C ₅ )alkyl groups;

m is 0, 1 or 2; and

repeating unit n is an integer from 1 to 50).

According to another aspect of the present invention, (a) preparing an active polymer by polymerizing an aromatic vinyl-based monomer and a conjugated diene-based monomer in the presence of an organic alkali metal compound in a hydrocarbon solvent; and

(b) reacting the active polymer with a modifier of formula (3):

[화학식 3]

[Formula 3]

(In Formula 3,

R ¹ , R ² and R ⁵ are each independently selected from the group consisting of hydrogen, a hydroxy group, a hydroxy (C ₁ -C ₂₀ )alkyl group, and a straight-chain and branched (C ₁ -C ₂₀ )alkyl group;

R ³ and R ⁴ are each independently selected from the group consisting of N, S, O and Si;

R ⁶ , R ⁷ and R ⁹ are each independently selected from the group consisting of hydrogen, straight-chain and branched (C ₁ -C ₂₀ )alkyl groups;

R ⁸ may be selected from the group consisting of straight-chain and branched (C ₁ -C ₂₀ )alkylene groups, or may form a single bond or a divalent linking group between N and Si;

R ¹⁰ and R ¹¹ are each independently selected from the group consisting of straight-chain and branched (C ₁ -C ₅ )alkyl groups;

m' is 0, 1, 2 or 3; and

The repeating unit n is an integer from 1 to 50), a method for preparing a copolymer is provided.

According to another aspect of the present invention, there is provided a rubber composition comprising the copolymer of the present invention and an inorganic filler.

According to another aspect of the present invention, there is provided a molded article prepared from the rubber composition of the present invention.

The novel modified copolymer provided by the present invention can obtain improved affinity for fillers such as silica, and furthermore, the effect of inhibiting aggregation between fillers in the rubber composition by such a modified structure can be obtained. have. As described above, the structure of the copolymer modified according to the present invention can further contribute to the improvement of fuel efficiency and maintain excellent dispersibility.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiment of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

In this specification, the term "includes" of any component means that other components may be further included, rather than excluding other components, unless otherwise stated.

As used herein, the term "hydrocarbon group" refers to a monovalent organic radical formed by removing a hydrogen atom from a hydrocarbon with a hydrocarbon group consisting only of carbon and hydrogen regardless of structure, such as an alkyl group, an aryl group, an alkylaryl group, an arylalkyl group, etc. not limited

In addition, the term “alkyl group” as used herein refers to a monovalent straight-chain, branched-chain or cyclic saturated hydrocarbon group composed of only carbon and hydrogen atoms, and includes a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, and an isobutyl group. group, t-butyl group, pentyl group, hexyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, and the like.

On the other hand, when forming a divalent linking group in the present invention, in this case, the linking group is an unsubstituted -(CH ₂ ) ₁ -hydrocarbon group or an alkyl having 1 to 10 carbon atoms which may include at least one unsaturated bond in the linking group. It could be a rengi. In this case, l may be an integer of 1 to 10.

The copolymer of the present invention (hereinafter, may be used interchangeably with the 'modified copolymer' and 'modified conjugated diene-based and aromatic vinyl-based copolymer of the present invention') can induce improved affinity with inorganic fillers, , it is also possible to secure excellent dispersibility by preventing re-agglomeration during polymerization.

More specifically, the modified copolymer of the present invention is a repeating unit derived from a conjugated diene-based monomer; and a repeating unit derived from an aromatic vinylic monomer, wherein at least one terminal among a plurality of terminals of the copolymer includes a functional group represented by Formula 1 above.

[화학식 1]

[Formula 1]

In Formula 1,

R ¹ , R ² and R ⁵ are each independently selected from the group consisting of hydrogen, a hydroxy group, a hydroxy (C ₁ -C ₂₀ )alkyl group, and a straight-chain and branched (C ₁ -C ₂₀ )alkyl group;

R ³ and R ⁴ are each independently selected from the group consisting of N, S, O and Si;

R ⁶ , R ⁷ and R ⁹ are each independently selected from the group consisting of hydrogen, straight-chain and branched (C ₁ -C ₂₀ )alkyl groups;

R ⁸ may be selected from the group consisting of straight-chain and branched (C ₁ -C ₂₀ )alkylene groups, or may form a single bond or a divalent linking group between N and Si;

R ¹⁰ and R ¹¹ are each independently selected from the group consisting of straight-chain and branched (C ₁ -C ₅ )alkyl groups;

m is 0, 1 or 2; and

The repeating unit n is an integer from 1 to 50.

The modified copolymer of the present invention contains an amino moiety, for example, a tertiary amino moiety, etc., thereby preventing aggregation between inorganic fillers when blended into a rubber composition, and as a result, the inorganic filler Dispersibility can be improved. For example, when silica is used as an inorganic filler, aggregation tends to occur due to hydrogen bonding between hydroxyl groups present on the silica surface. can improve the dispersibility of Furthermore, since the modified copolymer of the present invention includes an alkoxysilyl group, affinity with an inorganic filler that can improve abrasion resistance and processability of rubber products can be improved. For example, when the inorganic filler is silica, the abrasion resistance and workability of the conjugated diene-based and aromatic vinyl-based copolymers can be improved by condensation reaction with the silanol group on the surface of the silica.

More preferably, in the copolymer of the present invention, in Formula 1, R ¹ , R ² , R ⁵ and R ⁶ are each hydrogen; R ⁷ and R ⁹ are selected from the group consisting of a straight-chain (C ₁ -C ₂₀ )alkyl group; R ⁸ is a single bond between N and Si or a hydrocarbon group of -(CH ₂ ) _l -, wherein l is an integer of 1 to 10; R ³ and R ⁴ are each oxygen; R ¹⁰ and R ¹¹ are each independently selected from the group consisting of straight-chain and branched (C ₁ -C ₅ )alkyl groups; m is 0; and n is 1 or 2.

For example, the modified copolymer of Formula 1 is a modified conjugated diene-based and aromatic vinyl-based copolymer represented by Formula 2 below.

[화학식 2]

[Formula 2]

The copolymer of the present invention may be, for example, a conjugated diene-based copolymer and an aromatic vinyl-based copolymer, and in more detail, the conjugated diene-based and aromatic vinyl-based copolymer may be a styrene-butadiene copolymer represented by the following formula (4).

[화학식 4]

[Formula 4]

In Formula 4, x is preferably an integer of 500 to 5000, y is preferably an integer of 20 to 100, and the arrangement of the conjugated diene-based monomer and the aromatic vinyl-based monomer is limited to the arrangement of Formula 4 No, they may be randomly arranged random copolymers.

In the present specification, the 'monomer-derived repeating unit' may indicate a component, structure, or material itself derived from a monomer, and refers to a repeating unit formed in the polymer by participating in the polymerization reaction of the input monomer during polymerization of the polymer. can be one

Accordingly, in the present invention, the repeating unit derived from the conjugated diene-based monomer is 1,3-butadiene, isoprene, 1,3-pentadiene (piperylene), 2,3-dimethyl-1,3-butadiene, 1,3- Hexadiene, 2-methyl-1,3-pentadiene, 3,4-dimethyl-1,3-hexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octa It may include at least one selected from the group consisting of diene, 2-phenyl-1,3-butadiene, piperylene and isoprene. Specifically, the conjugated diene-based monomer may be 1,3-butadiene.

The repeating unit derived from the conjugated diene-based monomer is included in an amount of 60% to 99% by weight, or 60% to 90% by weight, specifically 63% to 85% by weight based on the weight of the conjugated diene-based and aromatic vinyl-based copolymer. can

The repeating unit derived from the aromatic vinyl-based monomer is styrene, alphamethyl styrene, 3-methyl styrene, 4-methyl styrene, 4-propyl styrene, 1-vinyl naphthalene, 4-cyclohexyl styrene, 4-(paramethylphenyl) styrene and 1 -Vinyl-5-hexylnaphthalene may include one or more selected from the group consisting of. Specifically, the aromatic vinyl-based monomer may be styrene.

The repeating unit derived from the aromatic vinyl-based monomer may be included in an amount of 10 wt% to 40 wt%, specifically 15 wt% to 40 wt%, based on the weight of the conjugated diene-based and aromatic vinyl-based copolymer.

The monomer mixture may further include a comonomer copolymerizable with a conjugated diene-based monomer and/or an aromatic vinyl-based monomer. Such a comonomer may include, but is not limited to, an acid anhydride-based monomer, an acrylonitrile-based monomer, and the like.

The modified copolymer obtained by the present invention may have a Mooney viscosity of 40 or more, specifically 40 to 90, more specifically 50 to 80. Since the Mooney viscosity is proportional to the weight average molecular weight, there may be an effect of improving mechanical properties within the above range.

On the other hand, the modified copolymer has a weight average molecular weight (Mw) of 1,000 g/mol to 2,000,000 g/mol, specifically 10,000 g/mol to 1,900,000 g/mol, more specifically 100,000 g/mol to 1,800,000 g/mol can be

In addition, the modified copolymer may have a molecular weight distribution (Mw/Mn, MwD) of from 1.0 to 10, or from 1.0 to 7, specifically from 1.1 to 5, and more specifically from 1.1 to 4.

Further, the modified copolymer may have a vinyl content of 60 wt% or more, specifically 63 wt% or more, and more specifically 63 wt% to 99 wt%. The vinyl content is 1,2, not 1,4-addition to the aromatic vinyl-based monomer, based on 100% by weight of the copolymer consisting of a monomer having a vinyl group and an aromatic vinyl-based monomer during copolymerization of the conjugated diene-based monomer and the aromatic vinyl-based monomer - It means the content of the added conjugated diene-based monomer.

In the viscoelastic characteristics of the modified copolymer, when measured at 10 Hz through dynamic mechanical analysis (DMA) after silica mixing, the Tan δ value at 60° C. may be 0.15 or less, and rolling resistance within this range Alternatively, the rotation resistance (RR) is greatly improved.

The copolymer of the modified copolymer of the present invention in a state before modification may be obtained by polymerizing a conjugated diene-based monomer or copolymerizing a vinyl aromatic monomer and a conjugated diene monomer.

According to another aspect of the present invention, there is provided a method for producing the modified copolymer of the present invention.

The polymerization step of the conjugated diene-based polymer is a step of preparing an alkali metal-bonded active polymer by polymerizing an aromatic vinyl-based monomer and a conjugated diene-based monomer in the presence of an organometallic compound in a hydrocarbon solvent. It may include a step representing

In more detail, the method for preparing the modified conjugated diene-based and aromatic vinyl-based copolymer of the present invention may include the following steps:

(a) preparing an active polymer by polymerizing an aromatic vinyl-based monomer and a conjugated diene-based monomer in a hydrocarbon solvent in the presence of an organic alkali metal compound; and

(b) reacting the active polymer with a modifier of formula (3):

[화학식 3]

[Formula 3]

In Formula 3,

R ¹ , R ² and R ⁵ are each independently selected from the group consisting of hydrogen, a hydroxy group, a hydroxy (C ₁ -C ₂₀ )alkyl group, and a straight-chain and branched (C ₁ -C ₂₀ )alkyl group;

R ³ and R ⁴ are each independently selected from the group consisting of N, S, O and Si;

R ⁶ , R ⁷ and R ⁹ are each independently selected from the group consisting of hydrogen, straight-chain and branched (C ₁ -C ₂₀ )alkyl groups;

R ⁸ may be selected from the group consisting of straight-chain and branched (C ₁ -C ₂₀ )alkylene groups, or may form a single bond or a divalent linking group between N and Si;

R ¹⁰ and R ¹¹ are each independently selected from the group consisting of a straight-chain (C ₁ -C ₅ )alkyl group;

m' is 0, 1, 2 or 3; and

The repeating unit n is an integer from 1 to 50.

Preferably, in the copolymer, in Formula 3, R ¹ , R ² , R ⁵ and R ⁶ are each hydrogen; R ⁷ and R ⁹ are selected from the group consisting of a straight-chain (C ₁ -C ₂₀ )alkyl group; R ⁸ is a single bond between N and Si or a hydrocarbon group of -(CH ₂ ) _l -, wherein l is an integer of 1 to 10; R ³ and R ⁴ are each oxygen; R ¹⁰ and R ¹¹ are each independently selected from the group consisting of straight-chain and branched (C ₁ -C ₅ )alkyl groups; m is 0; and n is 1 or 2.

Specific details regarding the conjugated diene-based monomer and the aromatic vinyl-based monomer may be the same as those described above with respect to the modified copolymer in the present specification, and the amount of each monomer used is a unit derived from a conjugated diene-based monomer and an aromatic vinyl-based monomer in the copolymer. The derived unit may be appropriately adjusted and used within the range controlled within the aforementioned range.

The hydrocarbon solvent is not particularly limited, but may be, for example, at least one selected from the group consisting of n-pentane, n-hexane, n-heptane, isooctane, cyclohexane, toluene, benzene and xylene. The hydrocarbon solvent may be used as it is, but it is preferable to use it after removing moisture, oxygen, or catalyst toxic substances by passing through molecular sieves and/or activated alumina.

The polymerization of step (a) may include anionic polymerization of the conjugated diene-based monomer and the aromatic vinyl-based monomer. In this case, the modified conjugated diene-based and aromatic vinyl-based copolymers are polymerized by generating an active site by a growth reaction with an anion initiated by an anionic polymerization initiator detailed below. However, the polymerization step of the present invention is not limited thereto.

In this case, the anionic polymerization initiator may include at least one selected from the group consisting of organic alkali metal compounds such as an organic lithium compound, an organic sodium compound, an organic potassium compound, an organic rubidium compound, and an organic cesium compound. It preferably contains an organolithium compound useful for polymerization of 1,3-diene monomer as an anionic polymerization initiator.

Specifically, the organolithium compound includes a compound composed of a lithium cation and an anion of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic group is a linear or branched alkyl group having 1 to 10 carbon atoms, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, sec-butyl, n-amine, sec-amyl, n -hexyl, sec-hexyl, n-heptyl, n-octyl, n-nonyl, etc., and the alicyclic hydrocarbon group is an alicyclic hydrocarbon group having 5 to 10 carbon atoms, for example, a cyclohexyl group, a methylcyclohexyl group, an ethylcyclohexyl group , cycloheptyl group, cyclopentylmethyl group, methylcyclopentylethyl group, etc., and the aromatic hydrocarbon group is an aryl group having 6 to 10 carbon atoms, for example, a phenyl group, tolyl group, phenylethyl group, benzyl group, naphthyl group or phenylcyclohexyl group.

Preferably, the anionic polymerization initiator is methyllithium, ethyllithium, propyllithium, n-butyllithium, s-butyllithium, t-butyllithium, hexyllithium, n-decyllithium, t-octyllithium, phenyllithium, 1- Naphthyllithium, n-eicosyllithium, 4-butylphenyllithium, 4-tolylylithium, cyclohexyllithium, 3,5-di-n-heptylcyclohexyllithium, 4-cyclopentyllithium, naphthyl sodium, naphthyl Potassium and the like may be included.

On the other hand, the anionic polymerization initiator is 0.0001 parts by weight to 0.65 parts by weight, for example, 0.00012 parts by weight to 0.64 parts by weight, 0.0002 parts by weight to 0.32 parts by weight, 0.0003 parts by weight to 0.16 parts by weight based on 100 parts by weight of the total of the monomer mixture. may be included. In the above range, it may be possible to prepare a copolymer having a high molecular weight.

The polymerization may be anionic polymerization, specifically, living anionic polymerization in which an active site is obtained by a growth reaction by an anion. In addition, the polymerization may be an elevated temperature polymerization, isothermal polymerization, or adiabatic polymerization (constant temperature polymerization).

Here, the adiabatic polymerization refers to a polymerization method comprising the step of polymerization with heat of reaction by itself without optionally applying heat after the organometallic compound is added, and the temperature-rising polymerization is a temperature by optionally adding heat after adding the organometallic compound. It represents a polymerization method to increase the temperature, and the isothermal polymerization refers to a polymerization method in which the temperature of the polymer is maintained constant by increasing heat by applying heat after the organometallic compound is added, or by taking heat away.

The polymerization may be carried out in a temperature range of -20 °C to 200 °C, specifically 0 °C to 150 °C, more specifically, it may be carried out in a temperature range of 10 °C to 120 °C.

In the polymerization of the copolymer in the state before modification, it may be polymerized by adding a polar additive. As such, the step polymerization may be performed by further adding a polar additive as necessary, and the polar additive is 0.005 g to 10 g, specifically 0.007 g to 7 g, more specifically 0.009 g based on 100 g of the total monomer. It may be added in g to 4g.

The polar additive may be a salt, an ether, an amine, or a mixture thereof. Specifically, tetrahydrofuran, ditetrahydrofurylpropane, diethyl ether, cycloamal ether, dipropyl ether, ethylene dimethyl ether, ethylene dimethyl ether, di Ethylene glycol, dimethyl ether, tertiary butoxyethoxyethane bis (3-dimethylaminoethyl) ether, (dimethylaminoethyl) ethyl ether, ethyl tetrafurfuryl ether, trimethylamine, triethylamine, tripropylamine and tetramethyl It may be at least one selected from the group consisting of ethylenediamine. More specifically, it may be ditetrahydrofurylpropane, ethyltetrafurfurylether, or tetramethylethylenediamine.

When the conjugated diene-based monomer and the aromatic vinyl-based monomer are copolymerized by using the polar additive, a random copolymer can be easily formed by compensating for a difference in their reaction rate.

The step (b) is a step of reacting the active polymer with the modifier represented by Formula 3 to prepare the modified copolymer.

The modifier represented by Chemical Formula 3 may be the same as described above, and may be one or a mixture of two or more used in the reaction.

The modifier represented by Formula 3 may be used in an amount of 0.1 mol to 10 mol relative to 1 mol of the organometallic compound. The modifier represented by Formula 3 may be used, for example, in an amount of 0.5 mol to 5 mol or less, preferably 1.2 mol to 2 mol per 1 mol of the organometallic compound. If the modifier is used in an amount that falls within the above ratio range, a coupling reaction with optimal performance may be performed, thereby obtaining the modified copolymer of the present invention.

The reaction of step (b) is a modification reaction for introducing a functional group into the copolymer, and may be performed at 0° C. to 90° C. for 1 minute to 5 hours.

In addition, the method for preparing the modified conjugated diene-based and aromatic vinyl-based copolymer may be performed by a batch method (batch type) or a continuous polymerization method including one or more reactive groups. The manufacturing method according to an embodiment of the present invention may further include one or more steps of recovering and drying the solvent and unreacted monomers as needed after the above step.

For example, the polymerization solvent, cyclohexane, can be used after passing through a tube filled with molecular sieve 5A and activated alumina and bubbling with high-purity nitrogen to sufficiently remove moisture, oxygen and other catalyst poisons. Styrene, a monomer, can be used after passing through a tube filled with activated alumina to sufficiently remove polymerization inhibitor, moisture, and oxygen.

All polymerizations can be carried out by adding an initiator after injecting a required amount of a solvent and each monomer to be polymerized in a high-pressure reactor (autoclave) completely blocked from external air.

In the viscoelastic characteristics of the conjugated diene-based and aromatic vinyl-based copolymers of the present invention, when measured at 10 Hz through DMA after silica mixing, the tan value at 60° C. is reduced, and rolling resistance or rotational resistance is improved This can lead to improved fuel economy performance.

According to another aspect of the present invention, there is provided a rubber composition comprising the modified conjugated diene-based and aromatic vinyl-based copolymer of the present invention and an inorganic filler. Through this, the molded article made of the rubber composition may have excellent fuel economy characteristics.

The rubber composition of the present invention may further include a filler in addition to the modified conjugated diene-based and aromatic vinyl-based copolymers. The modified conjugated diene-based and aromatic vinyl-based copolymers of the present invention have excellent affinity with fillers, so that the molded article obtained from the rubber composition of the present invention has excellent abrasion resistance, low rolling resistance, and high wet skid resistance, resulting in adjustment stability. can be excellent

The rubber composition of the present invention has a high tanδ measured at 0° C., and can have an effect of improving braking performance by improving wet resistance and roughing resistance, and improving fuel efficiency by improving rolling resistance and rolling resistance because tanδ measured at 60° C. is low It may work.

The filler may be included in an amount of 10 parts by weight to 200 parts by weight, preferably 50 parts by weight to 200 parts by weight, based on 100 parts by weight of the modified copolymer. Within the above range, the wear resistance may be excellent and there may be an effect of improving durability.

The filler may further include an organic filler commonly used in rubber compositions as well as inorganic fillers. For example, the organic filler may include one or more of carbon black and starch, and the inorganic filler may include one or more selected from the group consisting of silica, aluminum hydroxide, magnesium hydroxide, aluminum silicate and hydrated aluminum silicate. can Preferably, the filler may include silica, carbon black, or a combination thereof.

The rubber composition may further include a conjugated diene-based copolymer. The conjugated diene-based copolymer may include a homo-type copolymer of the above-described conjugated diene-based monomer. The conjugated diene-based copolymer is included in an amount of 10 parts by weight to 60 parts by weight, specifically 10 parts by weight to 50 parts by weight, more specifically 10 parts by weight to 30 parts by weight based on 100 parts by weight of the conjugated diene-based and aromatic vinyl-based copolymers. can Within the above range, there may be an effect of improving the physical properties of the rubber composition.

The rubber composition may further include an oil. The oils include vegetable oils such as paraffinic oil, aromatic oil, castor oil, mild extracted solvate (MES) oil, treated distillate aromatic extracted (TDAE) oil, low PCA oil including SRAE, heavy naphthenic oil, and black oil. It may include one or more types. The oil may be included in an amount of 1 part by weight to 100 parts by weight, specifically 10 parts by weight to 100 parts by weight, and more specifically 20 parts by weight to 80 parts by weight based on 100 parts by weight of the modified copolymer. Within the above range, the physical properties of the rubber composition may be well expressed and the rubber composition may be moderately softened to provide excellent processability.

The rubber composition may further include one or more additives commonly known to those skilled in the art in addition to fillers and oils, such as accelerators, waxes, fatty acids, processing aids, antioxidants, antioxidants, crosslinking agents, softeners, accelerators, and zinc oxide.

The additive may be included in an amount of 1 part by weight to 50 parts by weight, specifically 1 part by weight to 30 parts by weight, more specifically 1 part by weight to 10 parts by weight, based on 100 parts by weight of the modified conjugated diene-based and aromatic vinyl-based copolymer, respectively. . In the above range, it can serve as an additive without affecting the effectiveness of the rubber composition.

The rubber composition may be a vulcanized rubber composition further comprising sulfur. Sulfur is included in the rubber composition to form a network of rubber through a crosslinking reaction, thereby filling additives and improving durability. Sulfur may be included in an amount of 0.1 parts by weight to 50 parts by weight, specifically 0.1 parts by weight to 30 parts by weight, and more specifically 0.1 parts by weight to 10 parts by weight based on 100 parts by weight of the modified conjugated diene-based and aromatic vinyl-based copolymer. In the above range, the effect can be achieved without affecting the effect of the rubber composition.

Hereinafter, the molded article of this invention is demonstrated. According to another aspect of the present invention, there is provided a molded article prepared from the rubber composition of the present invention. The molded article may be a tire, tire tread, under-tread, sidewall, carcass coated rubber, belt coated rubber, bead filler, cheaper, or each member of the tire such as bead coated rubber, vibration proof rubber, belt conveyor, hose, etc. It can be various industrial rubber products. The molded article formed using the rubber composition may be a tire including a tire tread, and the molded article of the present invention exhibits only excellent fuel efficiency characteristics.

Hereinafter, the present invention will be described in more detail through specific examples. The following examples are only examples to help the understanding of the present invention, and the scope of the present invention is not limited thereto.

Example

1. Preparation of modified copolymer

(1) Synthesis of denaturant

1) Synthesis of 4-methylcatechol acetonide

4-Methyl catechol (30.0 g, 241.5 mmol), 2,2-Dimethoxypropane (87.36 g, 102.9 mL, 840 mmol), para-toluenesulfonic acid mono Hydrate (p-Toluenesulfonic acid monohydrate) (0.4 g, 2.0 mmol) and benzene (Benzene) (262.2 g, 300 mL) were placed in a 1 L, two-necked round bottom flask to prepare a uniform solution. After installing the succilet extraction device, the reaction was conducted at a temperature of 120° C. for 8 hours. After removing all of the solvent, the remaining material was purified through distillation under reduced pressure at 65° C. and a pressure of 1x10 ^-3 mbar to synthesize 4-methylcatechol acetonide in a pale yellow liquid state. (yield = 89%)

2) Synthesis of 4-Bromomethylcatechol acetonide (4-Bromomethylcatechol acetonide)

4-Methyl catechol acetonide (20.0 g, 121.8 mmol), N-Bromosuccinimide (21.6 g, 121.2 mmol), 2,2'-azobisiso Butyronitrile (2,2'-Azobisiso butyronitrile) (0.8 g, 4.88 mmol) and cyclohexane (262.2 g, 300 mL) were placed in a 1 L, two-necked round-bottom flask. After mounting a reflux cooler, the reaction was carried out at a temperature of 100° C. for 6 hours. Thereafter, the precipitated succinimide was filtered to remove, and all solvents of the remaining liquid material were removed to synthesize 4-Bromomethyl catechol acetonide in a yellow liquid state. (yield = 98%)

¹ H NMR (400 MHz, CDCl ₃ ): δ (ppm) = 6.84 (dd, 1H, Ar-C5H, 7.8 Hz, 1.8 Hz), 6.81 (d, 1H, ArC3H, 1.8 Hz), 6.68 (d, 1H) , ArCH, 7.8 Hz), 4.48 (s, 2H, CH ₂ Br), 1.70 (s, 6H, C(CH ₃ ) ₂ ).

3) Synthesis of N-methyl-3-(trimethoxysilyl)propylaminomethyl catechol acetonide (N-methyl-3-(trimethoxysilyl)propylaminomethylcatechol acetonide)

4-Bromomethyl catechol acetonide (4.88 g, 20.07 mmol), 3-Methyl Amino Propyl Trimethoxy-silane (3.88 g, 20.07 mmol) , Triethylamine (2.03 g, 20.07 mmol) and tetrahydrofuran (Tetrahydrofuran) (200 mL) were placed in a 500 mL, 1-necked round bottom flask and reacted at room temperature for 12 hours. The reaction solution was washed with a solvent in which water and methylene chloride were mixed in a ratio of 3:1, and then residual water was removed with magnesium sulfate. The solvent of the remaining liquid material was removed through distillation to synthesize a pale yellow liquid N-methyl-3-(trimethoxysilyl)propylaminomethyl catechol acetonide. (yield = 47%)

(2) Preparation of modified copolymer

Example 1: Modified copolymer using N-methyl-3-(trimethoxysilyl)propylaminomethyl catechol acetonide

After replacing the inside of the high-pressure reactor (internal capacity: 3 L, stainless steel) with nitrogen at room temperature, 2 L of cyclohexane, 50 mL of styrene, 178 g of 1,3-butadiene and 1.8 mL of polar additive ethyl tetrafurfuryl ether (monomer mixture) 0.34 parts by weight based on 100 parts by weight of the total amount of phosphorus styrene and 1,3-butadiene) was added. After that, the reactor temperature was preheated to 50° C., and 0.63 mmol of n-butyllithium (0.017 parts by weight based on 100 parts by weight of the total amount of styrene and 1,3-butadiene, a monomer mixture) was injected into the reactor, and then an adiabatic polymerization reaction was carried out. did After reacting for 30 minutes after reaching the maximum temperature, 1.26 mmol of N-methyl-3-(trimethoxysilyl)propylaminomethyl catechol acetonide, which is the denaturant obtained in (1) 3) above (1 mole of organometallic compound) 2 mol) and reacted for 60 minutes. Thereafter, ethanol was added to stop the reaction, the temperature was lowered to room temperature, and then a solution in which 1 phr of the antioxidant Songnox 1076 (based on 100 parts by weight of polymer) was dissolved in 20 mL of hexane was added. Then, the copolymer polymerization solution dispersed in the solvent was transferred to a container and dried for 15 hours or longer while heating at 80° C. in a vacuum oven to obtain a modified styrene-butadiene copolymer.

Comparative Example 1: Modified styrene-butadiene copolymer using 4-bromomethylcatechol acetonide

After replacing the inside of the high-pressure reactor (internal capacity: 3 L, stainless steel) with nitrogen at room temperature, 2 L of cyclohexane, 50 mL of styrene, 178 g of 1,3-butadiene and 1.8 mL of polar additive ethyl tetrafurfuryl ether (monomer) 0.34 parts by weight based on 100 parts by weight of the total amount of styrene and 1,3-butadiene as a mixture) was added. After that, the reactor temperature was preheated to 50° C., and 0.63 mmol of n-butyllithium (0.017 parts by weight based on 100 parts by weight of the total amount of styrene and 1,3-butadiene, a monomer mixture) was injected into the reactor, and then an adiabatic polymerization reaction was carried out. did After reaching the maximum temperature, the reaction was carried out for 30 minutes, and then 1.26 mmol of 4-bromomethylcatechol acetonide (2 moles relative to 1 mole of the organometallic compound) was added and reacted for 60 minutes. Ethanol was added to stop the reaction, the temperature was lowered to room temperature, and then a solution in which 1 phr of the antioxidant Songnox 1076 was dissolved in 20 mL of hexane was added. Then, the copolymer polymerization solution dispersed in the solvent was transferred to a container and dried for 15 hours or longer while heating at 80° C. in a vacuum oven to obtain a modified styrene-butadiene copolymer.

Comparative Example 2: Styrene-butadiene copolymer

A styrene-butadiene copolymer was obtained in the same manner as in Example 1, except that 4-methyl methylaminopropyltrimethoxysilyl catechol acetonide was not used in Example 1.

Comparative Example 3: Modified styrene-butadiene copolymer using catechol acetonide

200 g of 4-bromomethylcatechol acetonide-modified styrene-butadiene copolymer prepared according to the method of Comparative Example 1 was dissolved in 4 L of cyclohexane, and then 1 L of trichloroacetic acid was added and stirred at room temperature for 6 hours. Remove trichloroacetic acid using water and ethanol, add 10 mL of 28% aqueous ammonia to neutralize the remaining acid, transfer the copolymer polymerization solution to a container, and then heat to 80°C in a vacuum oven for at least 15 hours After drying, a modified styrene-butadiene copolymer was obtained.

2. Confirmation of the physical properties of the copolymer

The physical properties of the copolymers prepared in Examples and Comparative Examples were confirmed as follows, and are shown in Table 1 below.

1) The content of vinyl and styrene contained in the copolymer is determined by taking a small amount of each copolymer obtained in Examples and Comparative Examples, re-dissolving them in a CDCl3 solvent for NMR, and then taking them in small portions to obtain 500MHz 1H NMR (device name: Avance ^DRX400 , manufacturer). : Bruker).

2) Weight average molecular weight (Mw, unit: g/mol) and molecular weight distribution (Mw/Mn, MwD) for each copolymer obtained in Examples and Comparative Examples, GPC (Gel Permeation Chromatography, Device Name: PL-GPC220, Manufacturer) : Agilent) analysis method.

3) The glass transition temperature was measured by a differential scanning calorimetry (Differential Scanning Calorimetry, device name: Q200, TA Instruments) analysis method.

4) Mooney viscosity was measured and analyzed using a Mooney viscometer (MV2000, Alpha Technology) after preheating at 100 °C for 1 minute and then measuring for 4 minutes.

5) Pyrolyzer GC/MS: Pyrolysis gas chromatography mass spectrometry (pyrolyzer: JCI-55, JAI Corporation, GC/MS: Clarus 690T, perkinelmer) for each copolymer obtained in Examples and Comparative Examples Company, Column: DB-5MS 30m, Perkin-elmer) was evaluated through analysis.

6) Tan δ: Each copolymer obtained in Examples and Comparative Examples was put into an internal-type mixer with the composition shown in Table 2 below to prepare a formulation. The prepared formulation was compressed to obtain a specimen capable of measuring the tan δ of the formulation. For each of these specimens, tan δ at 60° C. was measured under conditions of 10 Hz and 0.2% strain using DMA (Dynamic Mechanical Analyzer, TA Instrument) as a temperature sweep test.

Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Styrene content (wt%) 21.1 21.1 21.0 21.3 Vinyl content (wt%) 65.0 65.3 62.0 67.1 Weight average molecular weight (Mw) 555,079 580,626 537,512 596,352 Molecular Weight Distribution (MwD) 1.13 1.14 1.07 1.16 Tg (℃) -25.2 -25.1 -25.7 -26.6 Mooney Viscosity (ML1+4, 100℃) 73.2 73.4 68.8 74.2

* Vinyl content (wt%): Vinyl weight/(butyene weight + vinyl weight) * 100

When preparing the modified styrene-butadiene copolymer of Example 1 and Comparative Example 1, the molecular weight was increased compared to Comparative Example 2. More specifically, in Comparative Example 1, 5-formyl-2,2-dimethyl-1,3-benzodioxole (5-formyl-2,2-dimethyl-1,3-benzodioxole (5- Formyl-2,2-Dimethyl-1,3-Benzodioxole) structure was confirmed to confirm that a modified structure was added to the end of the polymer, and in Example 1, 3-methylaminopropyltrimethoxysilane (3-Methyl Amino Propyl Trimethoxy-silane) structure was confirmed to be added at the end. On the other hand, Comparative Example 3 was prepared through a deprotection process using the polymer of Comparative Example 1, and as a result, the structure of the acetonide derivative was not detected in Pyrolyzer GC/MS, so that all acetonide groups were catechol. (catechol) group can be expected to be converted .

3. Preparation of tire tread composition and confirmation of physical properties

(1) Preparation of tire tread composition

A tire tread rubber composition was prepared by mixing and kneading the polymers obtained in each of Examples and Comparative Examples in the composition shown in Table 2 below.

More specifically, the styrene-butadiene copolymer (SSBR) prepared in each of the above Examples and Comparative Examples was put into a Banbari mixer, and silica, carbon black, anti-aging agent, softener, cross-linking aid, cross-linking agent, etc. were added as a compounding material. A tire tread rubber composition was obtained by adding and blending in the same amount as shown in Table 2 below, which are referred to as Experimental Example 1 and Comparative Experimental Examples 1 to 3, respectively, and SSBR items in Table 2 below are Example 1, and Comparative Examples It means that the corresponding copolymer among the styrene-butadiene copolymers (SSBR) prepared in steps 1 to 3 is added.

substance name content (phr; parts by weight) SSBR 80.0 Butadiene rubber 20.0 Silica (7000GR) 80.0 TDAE oil 37.5 ZnO 3.0 stearic acid 1.0 X50S coupling agent 12.8 Antioxidant 6PPD 2.0 Anti-aging agent RD (POLYMERIZED 2.2.4-TRIONETHYL-1.2-DIHYDROQUINOLINE) 1.0 Anti-aging agent WAX 2.0 Accelerator CZ (CBS) 1.7 Accelerator D (DPG) 2.0 Sulfur 1.9

(2) Checking the physical properties of the tire tread - loss factor

A tire tread sample was prepared using each tire tread composition obtained in 3.(1) above, and a tan delta value, which is a loss coefficient, was measured using each of them at a temperature of 60° C., and is shown in Table 3.

Experimental Example 1 Comparative Experimental Example 1 Comparative Experimental Example 2 Comparative Experimental Example 3 tan δ 60℃ 0.131 0.144 0.151 0.146

Referring to Table 3, it was confirmed that the sample of Experimental Example 1 had a lower tan delta value, which is a loss coefficient at a temperature of 60°C, compared to the samples of Comparative Experimental Examples that were not denatured. As such, the loss coefficient was Reduction means that silica and rubber are not easily separated due to dynamic deformation. As a result, the tire emits low energy during rotation, which reduces heat loss, lowering rolling resistance, and consequently improving fuel efficiency. can act to make In particular, in the case of Experimental Example 1 using the modified copolymer of Example 1, it was possible to obtain a significant decrease in the tan delta value.

In the case of Comparative Experimental Example 3 using the modified copolymer of Comparative Example 3, the overall tan δ value at 60° C. was high, which was rather due to re-aggregation of molecules due to the strong electrophilic properties of the catechol structure. It was confirmed that there was no significant influence on the silica dispersibility in the formulation. In the results of Example 1, it was possible to further lower tan δ at 60° C. compared to adding a tertiary amino group and an alkoxysilyl group to the existing Catechol acetonide structure.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and variations are possible within the scope without departing from the technical spirit of the present invention described in the claims. It will be apparent to those of ordinary skill in the art.

Claims (9)

a repeating unit derived from a conjugated diene-based monomer; and
It is a copolymer comprising a repeating unit derived from an aromatic vinylic monomer,
A copolymer in which at least one terminal among a plurality of ends of the copolymer includes a functional group represented by the following formula (1):
[Formula 1]

(In Formula 1,
R ¹ , R ² and R ⁵ are each independently selected from the group consisting of hydrogen, a hydroxy group, a hydroxy (C ₁ -C ₂₀ )alkyl group, and a straight-chain and branched (C ₁ -C ₂₀ )alkyl group;
R ³ and R ⁴ are each independently selected from the group consisting of N, S, O and Si;
R ⁶ , R ⁷ and R ⁹ are each independently selected from the group consisting of hydrogen, straight-chain and branched (C ₁ -C ₂₀ )alkyl groups;
R ⁸ may be selected from the group consisting of straight-chain and branched (C ₁ -C ₂₀ )alkylene groups, or may form a single bond or a divalent linking group between N and Si;
R ¹⁰ and R ¹¹ are each independently selected from the group consisting of straight-chain and branched (C ₁ -C ₅ )alkyl groups;
m is 0, 1 or 2; and
repeating unit n is an integer from 1 to 50).
According to claim 1, wherein Formula 1 is,
R ¹ , R ² , R ⁵ and R ⁶ are each hydrogen;
R ⁷ and R ⁹ are selected from the group consisting of a straight-chain (C ₁ -C ₂₀ )alkyl group;
R ⁸ is a single bond between N and Si or a hydrocarbon group of -(CH ₂ ) _l -, wherein l is an integer of 1 to 10;
R ³ and R ⁴ are each oxygen;
R ¹⁰ and R ¹¹ are each independently selected from the group consisting of straight-chain and branched (C ₁ -C ₅ )alkyl groups;
m is 0; and
n is 1 or 2;
The copolymer according to claim 1, wherein Chemical Formula 1 is represented by Chemical Formula 2 below.
[Formula 2]

(a) preparing an active polymer by polymerizing an aromatic vinyl-based monomer and a conjugated diene-based monomer in a hydrocarbon solvent in the presence of an organic alkali metal compound; and
(b) a method for preparing a copolymer comprising the step of reacting the active polymer with a modifier of formula (3):
[Formula 3]

(In Formula 3,
R ¹ , R ² and R ⁵ are each independently selected from the group consisting of hydrogen, a hydroxy group, a hydroxy (C ₁ -C ₂₀ )alkyl group, and a straight-chain and branched (C ₁ -C ₂₀ )alkyl group;
R ³ and R ⁴ are each independently selected from the group consisting of N, S, O and Si;
R ⁶ , R ⁷ and R ⁹ are each independently selected from the group consisting of hydrogen, straight-chain and branched (C ₁ -C ₂₀ )alkyl groups;
R ⁸ may be selected from the group consisting of straight-chain and branched (C ₁ -C ₂₀ )alkyl groups, or may form a single bond or a divalent linking group between N and Si;
R ¹⁰ and R ¹¹ are each independently selected from the group consisting of straight-chain and branched (C ₁ -C ₅ )alkyl groups;
m' is 0, 1, 2 or 3; and
repeating unit n is an integer from 1 to 50).
5. The method of claim 4, wherein Formula 3 is,
R ¹ , R ² , R ⁵ and R ⁶ are each hydrogen; R ⁷ and R ⁹ are selected from the group consisting of a straight-chain (C ₁ -C ₂₀ )alkyl group; R ⁸ is a single bond between N and Si or a hydrocarbon group of -(CH ₂ ) _l -, wherein l is an integer of 1 to 10; R ³ and R ⁴ are each oxygen; R ¹⁰ and R ¹¹ are each independently selected from the group consisting of straight-chain and branched (C ₁ -C ₅ )alkyl groups; m is 0; and n is 1 or 2.
A rubber composition comprising the copolymer of any one of claims 1 to 3 and an inorganic filler.
The rubber composition according to claim 6, wherein the inorganic filler is at least one selected from the group consisting of silica, aluminum hydroxide, magnesium hydroxide, aluminum silicate and hydrated aluminum silicate.
A molded article prepared from the rubber composition of claim 7.
The molded article of claim 8 , wherein the molded article is a tire comprising a tire tread.